Identifier.java

/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Lars Vogel <Lars.Vogel@vogella.com> - Bug 472654
 *******************************************************************************/

package org.eclipse.ui.internal.activities;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import org.eclipse.core.runtime.ListenerList;
import org.eclipse.ui.activities.IIdentifier;
import org.eclipse.ui.activities.IIdentifierListener;
import org.eclipse.ui.activities.IdentifierEvent;
import org.eclipse.ui.internal.util.Util;

final class Identifier implements IIdentifier {
    private final static int HASH_FACTOR = 89;

    private final static int HASH_INITIAL = Identifier.class.getName()
            .hashCode();

	private final static Set<Identifier> strongReferences = new HashSet<>();

	private Set<String> activityIds = Collections.emptySet();

    private transient String[] activityIdsAsArray = {};

    private boolean enabled;

    private transient int hashCode = HASH_INITIAL;

    private String id;

	private ListenerList<IIdentifierListener> identifierListeners;

    private transient String string;

    Identifier(String id) {
        if (id == null) {
			throw new NullPointerException();
		}

        this.id = id;
    }

    @Override
	public void addIdentifierListener(IIdentifierListener identifierListener) {
        if (identifierListener == null) {
			throw new NullPointerException();
		}

        if (identifierListeners == null) {
			identifierListeners = new ListenerList<>(ListenerList.IDENTITY);
		}

		identifierListeners.add(identifierListener);
        strongReferences.add(this);
    }

    @Override
	public int compareTo(Object object) {
        Identifier castedObject = (Identifier) object;
        int compareTo = Util.compare(activityIdsAsArray,
                castedObject.activityIdsAsArray);

        if (compareTo == 0) {
            compareTo = Util.compare(enabled, castedObject.enabled);

            if (compareTo == 0) {
				compareTo = Util.compare(id, castedObject.id);
			}
        }

        return compareTo;
    }

    @Override
	public boolean equals(Object object) {
        if (!(object instanceof Identifier)) {
			return false;
		}

        final Identifier castedObject = (Identifier) object;
        if (!Util.equals(activityIds, castedObject.activityIds)) {
            return false;
        }

        if (!Util.equals(enabled, castedObject.enabled)) {
            return false;
        }

        return Util.equals(id, castedObject.id);
    }

    void fireIdentifierChanged(IdentifierEvent identifierEvent) {
        if (identifierEvent == null) {
			throw new NullPointerException();
		}

        if (identifierListeners != null) {
			for (IIdentifierListener listener : identifierListeners) {
				listener.identifierChanged(identifierEvent);
			}
		}
    }

	@Override
	public Set<String> getActivityIds() {
        return activityIds;
    }

    @Override
	public String getId() {
        return id;
    }

    @Override
	public int hashCode() {
        if (hashCode == HASH_INITIAL) {
            hashCode = hashCode * HASH_FACTOR + Util.hashCode(activityIds);
            hashCode = hashCode * HASH_FACTOR + Util.hashCode(enabled);
            hashCode = hashCode * HASH_FACTOR + Util.hashCode(id);
            if (hashCode == HASH_INITIAL) {
				hashCode++;
			}
        }

        return hashCode;
    }

    @Override
	public boolean isEnabled() {
        return enabled;
    }

    @Override
	public void removeIdentifierListener(IIdentifierListener identifierListener) {
        if (identifierListener == null) {
			throw new NullPointerException();
		}

        if (identifierListeners != null) {
			identifierListeners.remove(identifierListener);
			if (identifierListeners.isEmpty()) {
				strongReferences.remove(this);
			}
		}
    }

	boolean setActivityIds(Set<String> activityIds) {
		activityIds = Util.safeCopy(activityIds, String.class);

        if (!Util.equals(activityIds, this.activityIds)) {
            this.activityIds = activityIds;
			this.activityIdsAsArray = this.activityIds.toArray(new String[this.activityIds.size()]);
            hashCode = HASH_INITIAL;
            string = null;
            return true;
        }

        return false;
    }

    boolean setEnabled(boolean enabled) {
        if (enabled != this.enabled) {
            this.enabled = enabled;
            hashCode = HASH_INITIAL;
            string = null;
            return true;
        }

        return false;
    }

    @Override
	public String toString() {
        if (string == null) {
            final StringBuffer stringBuffer = new StringBuffer();
            stringBuffer.append('[');
            stringBuffer.append(activityIds);
            stringBuffer.append(',');
            stringBuffer.append(enabled);
            stringBuffer.append(',');
            stringBuffer.append(id);
            stringBuffer.append(']');
            string = stringBuffer.toString();
        }

        return string;
    }
}